My EEE PC hangs on bootup if it is not connected to mains power. Thehang happens during udev coldplug. I've left it for >60 seconds withnmi_watchdog=1, soft lockup and hung task detection are enabled, and Iget no trace. Key presses are not echoed to the screen.

Magic SysRQ keys work though. Unfortunately, SysRq-W / SysRq-T generatetoo much output, so the useful bits immediately scroll off the top ofthe screen. I can't press SysRq-P (even if that would help), becausethe SysRQ key on my laptop is accessed using a Fn modifier key, whichalso turns the left hand side of the keyboard into a numeric pad.

Magic SysRQs on my USB keyboard generate no response. (Sometimes thenumlock key seems to work though. I can't tell on the laptop keyboardbecause the laptop doesn't have a numlock led).

I also tried booting with vga=ask (anticipating nmi_watchdog output),and selecting the highest mode, 80x60. It turns out that this doesn'treally work, the screen flickers constantly until userspace changes theconsole font. However, it avoided the hang in udev coldplug. Instead,the hang occurred when X started, leaving me with a black screen and anon-responsive X cursor.